login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A189594 Number of permutations of 1..n with displacements restricted to {-6,-5,-4,-3,-1,0,2} 1
1, 1, 2, 4, 10, 23, 51, 111, 225, 469, 997, 2125, 4569, 9742, 20728, 44075, 93629, 199251, 424146, 902940, 1922351, 4091125, 8706560, 18528914, 39433024, 83926690, 178622780, 380165386, 809106324, 1722001443, 3664905891, 7799962633 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-3) +2*a(n-4) +5*a(n-5) +4*a(n-6) +9*a(n-7) +13*a(n-8) -5*a(n-9) +6*a(n-10) -17*a(n-11) -14*a(n-12) -2*a(n-13) -11*a(n-14) -2*a(n-15) -11*a(n-16) -4*a(n-17) -2*a(n-18) +5*a(n-19) +7*a(n-20) +2*a(n-21) +2*a(n-22) +2*a(n-23) +a(n-24) +a(n-25) +a(n-26) -a(n-27) -a(n-28)

EXAMPLE

Some solutions for n=11

..1....4....1....1....1....1....1....2....4....1....6....1....1....5....5....4

..2....7....2....6....7....5....7....8....3....5....5....2....5....3....2....3

..3....1....3....3....6....4....3....1....1....6....1....7....3....1....1....1

..5....2....7....2....2....2....2....5....2....2....2....4....2....2....4....2

..6....3....5....5....3....3....9....3....6....3....3....3....6....6....3....6

..4...10....4....4....4...11....4....4....7....4....4....6....4....4....6...10

.10....5...10....7....5....8....5...10....5....7....8....5....8....7....8....5

.11....6....6...11...11....6....6....6...11....8....9...11...11....8....9....8

..7....9....9...10...10....7...10....7...10...10....7...10....7....9....7....7

..8....8....8....8....8...10....8...11....8...11...10....8...10...10...10...11

..9...11...11....9....9....9...11....9....9....9...11....9....9...11...11....9

CROSSREFS

Sequence in context: A189587 A345195 A018111 * A094987 A189601 A210460

Adjacent sequences:  A189591 A189592 A189593 * A189595 A189596 A189597

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 24 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 3 00:59 EST 2021. Contains 349445 sequences. (Running on oeis4.)